The present invention generally relates to a joint for pneumatic ducting and, more specifically, to a low profile tension style flexible joint for pneumatic ducting for apparatus such as gas turbine engines.
Gas turbine (“jet”) engines may be used to provide the thrust needed to propel aircraft. Additionally, by redirecting a portion of the compressed air produced by the engines through a conduit system, the air can be used for a variety of other purposes. These other purposes include pressurizing, heating, and cooling the aircraft's cabin, deicing its wings and engine cowlings, and removing moisture from its front windows.
Due to variations in pressure, temperature, wind, and other factors which influence an aircraft in flight and the stresses caused during takeoffs and landings, the conduit system can experience frequent and sudden changes in its position. To minimize any adverse effect of these changes on the integrity of the conduit system, flexible joints connecting rigid duct sections have been proposed and utilized. To be of use, the duct joints must not only permit rotational and angular movement between the rigid ducts, but they must do so with minimum leakage of the compressed air passing through the system. Consequently, such joints must not only permit rotational and angular movement, but they must also include a low leakage seal to minimize escape of the air.
Tension style flexible joints are a special type of flexible joint which internally support the axial load inherent in pressurized ducting systems, a characteristic which becomes particularly important in high pressure applications that generate large axial loads. The use of tension style flexible joints for high pressure applications eliminates the need for external supports and reduces the chances of fatigue failures in the pneumatic ducting systems.
In many of today's modern turbomachines, such as turbo-powered aircraft, both overall engine weight and size are issues of concern for engineers. Reduced engine size and lower weight goals have required smaller installation envelopes for the jet engine, including the pneumatic ducting used thereupon.
Accordingly, there is a need for an improved duct joint that permits rotational and angular movement between duct sections, minimizes the escape of compressed air through the conduit system, and allows for installation in an installation envelope of minimal size.